An ink jet recording method which discharges ink on a recording medium to perform recording can be cited as an example in which a liquid discharge head for discharging a liquid is used.
The ink jet recording head to which the ink jet recording method is adopted usually includes an ink discharge port, an ink flow path, and an energy generating element. The energy generating element is provided in a part of the flow path, and generates energy for discharging the ink. Conventionally, for example, there is known a following method as the method of producing the ink flow path of the recording head.
In the producing method disclosed in U.S. Pat. No. 5,478,606, a pattern which becomes a mold of the ink flow path is formed with a soluble resin on a substrate in which the energy generating elements are formed, and a coating resin layer which becomes an ink flow path wall is formed on the mold pattern of the ink flow path. Then, orifices are formed on the energy generating element by photolithography, and the mold pattern of the ink flow path is eluted to cure the coating resin layer which becomes the ink flow path wall.
Recently, as high speed and high image quality are demanded in the ink jet printer, the flow path becomes miniaturized in the ink jet recording head.
For the method of forming the ink flow path with the pattern which becomes the mold, for example, as described in U.S. Pat. No. 6,986,980, a three-dimensional shape is optimized in the miniaturized ink flow path to achieve the speedup of ink refill.
In the method disclosed in U.S. Pat. No. 6,986,980, a first positive-type photosensitive material layer which is photosensitive to light having a first wavelength range while cross-linked is provided on the substrate in which the energy generating elements are formed, and the first positive-type photosensitive material layer is heated to form the cross-linked positive-type photosensitive material layer (lower layer). Then, a double-layer structure is formed by providing an upper layer including a second positive-type photosensitive material on the lower layer. The second positive-type photosensitive material is photosensitive to light having a second wavelength range which is different from the first wavelength range. Then, a predetermined portion of the upper layer of the double-layer structure is irradiated with the light having the second wavelength range. Subsequently, the irradiated region of the upper layer is removed to obtain a desired pattern by performing a development process. Then, a predetermined region of the lower layer which is exposed by the pattern formation of the upper layer is irradiated with the light having the first wavelength range, and the desired pattern is formed in the lower layer by performing the development process. Thus, the pattern which becomes the mold of the flow path is produced through the above steps.
However, in the ink jet recording head producing method described in U.S. Pat. No. 6,986,980, it is necessary to use two kinds of exposure wavelengths. Therefore, there is a problem that a process load is increased by complicating the process.